A school-based program to prevent obesity may also be effective in preventing adolescent girls from vomiting or using laxatives or diet pills to control their weight, new study findings show.

"Obesity and eating disorders are very serious health issues for adolescent girls, and school-based programs need to be able to address both of them," study author Dr. S. Bryn Austin of Children's Hospital in Boston, Massachusetts stated.

"Ours is apparently the first study to find that prevention of both obesity and eating disorder symptoms can be done in the same program," Austin said, adding that although the "findings are promising, it is too early to know yet if other studies will find the same beneficial effect."

Austin and her team randomly assigned 10 middle schools to an intervention -- the Planet Health obesity prevention program -- or a control group for two school years.

The Planet Health program, designed to promote healthy eating and physical activity and to reduce television viewing, was fully integrated into the schools' curriculum, including math, science and other classroom lessons as well as physical activity lessons. The program did not involve explicit mention of eating disorders, weight control or body image.

At the end of the 21-month study period, the investigators analyzed data about the weight-control behaviors of 480 10- to 14-year old girls. None of the girls had previously reported purging or using diet pills.

They found that approximately 3 percent of girls in schools that participated in the obesity prevention program reported purging or using diet pills as a means of controlling their weight, compared with 6 percent of girls in schools where the program had not been implemented, the researchers report in Archives of Pediatrics and Adolescent Medicine.

"This means that roughly half of the new cases of girls using these dangerous weight-control methods that we might have expected to see may have been prevented by Planet Health," Austin said.

"The protective effect that we found may be stronger than any other eating disorder prevention program to date that we are aware of," she added.

In the same issue of the journal, editorialist Dr. Dianne Neumark-Sztainer, of the University of Minnesota's School of Public Health, writes that Austin's "excellent study provides promising evidence that well-designed interventions may effectively integrate prevention of both obesity and disordered weight-control behaviors."

In order to prevent obesity and unhealthy weight control behaviors, however, efforts must be made not only in school, but outside school as well, according to Austin.

"Creating healthy environments for kids is really everyone's responsibility," Austin said. "Schools have an important role in prevention, but so do parents, other family members, neighbors, community leaders, elected officials, and the media."

SOURCE: Archives of Pediatrics and Adolescent Medicine, March 2005.